Flavor mostly. Ceci Love is a wonderful mango, and one of my top 3 if not top. It just is so good. My first intro to it wasn't that great. Then had some properly ripened ones. Have to grow it. Re: growth, etc, not enough is known about Ceci Love grafted trees.
Added several scions to our Glenn tree, and was able to get a successful graft onto a Glenn seedling volunteer that popped up underneath a Norfolk pine. While the top work grafts are pleasing, can't tell you how happy it makes me to know that we are growing a tree solely bearing this fruit. Being a collector of favorite fruits that cannot be easily bought elsewhere, not having this tree/fruit in our collection would be silly.
That being said, Pickering is a great all around mango, and not a bad choice. I love it.
I gifted a Pickering to a friend who had no fruit trees for that reason (all around awesomeness). They are Miami natives, and said the mangoes were the best they've ever had. They are not mango maniacs like many of us though, and have never tried most of the ones we rave about.
As for flavor groups, no coconut flavor in CL like you can find in Pickering. Pickering has a sweet and balanced mango flavor, low to no fiber. CL is super sweet and has a mild tart component, and some spice, depending on ripeness. No to low fiber.
Here is a great idea; grow both!!! You will love each of them, but CLs will taste better.